1. Field of the Invention
The present invention is generally in the field of semiconductor die packaging. More specifically, the present invention is in the field of semiconductor die and discrete component packaging.
2. Background Art
The requirement of smaller, more complex, and faster devices operating at high frequencies, such as wireless communications devices and Bluetooth RF transceivers, has also resulted in an increased demand for small size antennas. Further, the decrease in size of wireless communication devices has created a demand for a small size antenna that is integrated in the same xe2x80x9cpackagexe2x80x9d housing the semiconductor die coupled to the antenna. However, integrating an antenna in the package housing the semiconductor die presents technical challenges.
For example, the antenna has to be miniaturized to enable the antenna to fit in the semiconductor die package. Also, the miniaturized antenna must be able to operate at high frequencies, such as the Bluetooth frequency range of approximately 2.40 GHz to 2.48 GHz. Although there are miniaturized antennas that are commercially available, these conventional miniaturized antennas are available only in a stand-alone configuration. In other words, these miniaturized antennas are available in a package that does not contain a semiconductor die. The stand-alone miniature antennas typically require relatively long interconnect lines to couple the stand-alone antennas to a transceiver or other device. The long interconnect lines result in xe2x80x9cline lossesxe2x80x9d that decrease the performance of the wireless communication device.
As another example, since a stand-alone miniature antenna is a discrete component, the stand-alone miniature antenna requires assembly on a printed circuit board in the wireless communication device. Thus, the required assembly of the miniature antenna results in an increase in the manufacturing cost of the wireless communication device.
Another technical challenge in integrating an antenna in the package housing the semiconductor die is to sufficiently shield the semiconductor die from the antenna to avoid compromising the performance of the semiconductor die. Also, the antenna needs to be shielded from elements in the environment that can decrease the antenna""s efficiency. In one approach to this challenge, a semiconductor die is mounted upside down in a cavity formed in the bottom of a multilayer ceramic substrate. In this approach, an antenna is fabricated above the semiconductor die in a metal layer in the multilayer ceramic substrate, and a ground plane is fabricated in a metal layer situated between the semiconductor die and the antenna. Thus, the ground plane utilized in this approach shields the semiconductor die from electromagnetic field radiated by the antenna. However, the above approach does not shield the sides of the antenna from the environment.
A slot antenna for semiconductor applications was reported in a paper by H. Rogier et al., xe2x80x9cDesign of an On-Package Slot Antenna for Bluetooth Applications,xe2x80x9d Proceedings of the 9th IEEE Topical Meeting on Electrical Performance of Electronic Packaging, pp. 292-295, Oct. 23-25, 2000 (European Patent no. 120418N pending). However, the slot antenna disclosed by Rogier et at, does not overcome various technical challenges such as those mentioned above.
Therefore, there exists a need for a properly shielded antenna that can be integrated in a semiconductor die package without increasing the manufacturing cost of the semiconductor die package.
The present invention is directed to a shielded antenna in a semiconductor package. The present invention overcomes the need in the art for a properly shielded antenna element that can be integrated in a semiconductor die package without increasing the manufacturing cost of the semiconductor die package by shielding the sides of an antenna fabricated on the bottom surface of a laminate substrate which also houses a semiconductor die.
One exemplary embodiment of the present invention is a structure comprising a laminate substrate having a top surface for receiving a semiconductor die. The laminate substrate can comprise an organic or ceramic material. The exemplary structure further comprises an antenna element situated on a bottom surface of the laminate substrate, where the antenna element is suitable for connection to the semiconductor die. The shape of the antenna element can be, for example, a square shape, a rectangular shape, a slot line pattern, a meander line pattern, or a patch pattern.
According to this exemplary embodiment, the structure further comprises a laminate substrate reference pad in the laminate substrate, where the laminate substrate reference pad is situated over the antenna element. The laminate substrate reference pad is generally at ground voltage, in which case it is referred to as a laminate substrate ground pad. The exemplary structure further comprises at least one laminate substrate reference via situated at a side of the antenna element. The at least one laminate substrate reference via can be electrically connected to the laminate substrate reference pad. By way of example, the at least one laminate substrate reference via can be at ground voltage in which case it is referred to as a laminate substrate ground via. The at least one laminate substrate reference via can be electrically coupled to a printed circuit board reference via in a printed circuit board. Moreover, the printed circuit board reference vias might be connected to a printed circuit board reference pad.